[ovirt-users] Re: Multipath flapping with SAS via FCP

26 Feb 2021

      Hi Nir Soffer,
Thank for your reply

Indeed, the device fails immediately after it was reinstated.

There is my 'multipathd show config' dump :

defaults {
	verbosity 2
	polling_interval 5
	max_polling_interval 20
	reassign_maps "no"
	multipath_dir "/lib64/multipath"
	path_selector "service-time 0"
	path_grouping_policy "failover"
	uid_attribute "ID_SERIAL"
	prio "const"
	prio_args ""
	features "0"
	path_checker "tur"
	alias_prefix "mpath"
	failback "manual"
	rr_min_io 1000
	rr_min_io_rq 1
	max_fds 4096
	rr_weight "uniform"
	no_path_retry 16
	queue_without_daemon "no"
	flush_on_last_del "yes"
	user_friendly_names "no"
	fast_io_fail_tmo 5
	dev_loss_tmo 60
	bindings_file "/etc/multipath/bindings"
	wwids_file "/etc/multipath/wwids"
	prkeys_file "/etc/multipath/prkeys"
	log_checker_err always
	all_tg_pt "no"
	retain_attached_hw_handler "yes"
	detect_prio "yes"
	detect_checker "yes"
	force_sync "no"
	strict_timing "no"
	deferred_remove "no"
	config_dir "/etc/multipath/conf.d"
	delay_watch_checks "no"
	delay_wait_checks "no"
	san_path_err_threshold "no"
	san_path_err_forget_rate "no"
	san_path_err_recovery_time "no"
	marginal_path_err_sample_time "no"
	marginal_path_err_rate_threshold "no"
	marginal_path_err_recheck_gap_time "no"
	marginal_path_double_failed_time "no"
	find_multipaths "on"
	uxsock_timeout 4000
	retrigger_tries 3
	retrigger_delay 10
	missing_uev_wait_timeout 30
	skip_kpartx "no"
	disable_changed_wwids ignored
	remove_retries 0
	ghost_delay "no"
	find_multipaths_timeout -10
	enable_foreign ""
	marginal_pathgroups "no"
}
blacklist {
	devnode "!^(sd[a-z]|dasd[a-z]|nvme[0-9])"
	wwid "36f402700f232e40026b41bd43a0812e5"
	protocol "(scsi:adt|scsi:sbp)"
...
}
blacklist_exceptions {
	protocol "scsi:sas"
}
devices {
...
	device {
		vendor "COMPELNT"
		product "Compellent Vol"
		path_grouping_policy "multibus"
		no_path_retry "queue"
	}
...
}
overrides {
	no_path_retry 16
}

And there is my scsi disks (sdb & sdc disks) :

[root@anarion-adm ~]# lsscsi -l
[0:2:0:0]    disk    DELL     PERC H330 Adp    4.30  /dev/sda                                      
  state=running queue_depth=256 scsi_level=6 type=0 device_blocked=0 timeout=90
[1:0:0:2]    disk    COMPELNT Compellent Vol   0704  /dev/sdb 
  state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30
[1:0:1:2]    disk    COMPELNT Compellent Vol   0704  /dev/sdc 
  state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30

My disk configuration is present in multipath, and the DELLEMC documentation & white paper don't specifying exotics configuration for multipathd. (I'm wrong ?)

I looked modules for SAS & FCP driver, they look good : 

[root@anarion-adm ~]# lsmod | grep sas
mpt3sas               303104  4
raid_class             16384  1 mpt3sas
megaraid_sas          172032  2
scsi_transport_sas     45056  1 mpt3sas

[root@anarion-adm ~]# lsmod | grep fc
bnx2fc                110592  0
cnic                   69632  1 bnx2fc
libfcoe                77824  2 qedf,bnx2fc
libfc                 147456  3 qedf,bnx2fc,libfcoe
scsi_transport_fc      69632  3 qedf,libfc,bnx2fc

Do you think my device is misconfigured? should I check on the vendor side?  Another idea ? :)

Regards,
Benoit Chatelain